1. Field of the Invention
The present invention relates to a data transmission device or system wherein a central control unit and a plurality of terminals are connected by a transmission line, the data transmission system being for transmitting information data from the central control unit to the terminals.
2. Description of the Related Art
Conventionally, there is known a data transmission system, wherein a center (central control unit) is connected to a plurality of terminals by a transmission line. The data transmission system is for transmitting information data including various types of information from the center to the terminal according to demands from the terminal side. An advantage of this type of data transmission system is that a memory device for prestoring data information need not be provided to each terminal, so that the terminals have an extremely simple construction.